1. Field of the Invention
The subject invention is directed to surveillance and monitoring systems and is specifically directed to a comprehensive, hybrid multimedia surveillance system based on wireless data transmission, still image and/or step video, video streaming, audio, motion detection, event detection and/or physical condition detection using various network configurations including both wired and wireless Local Area Network (LAN) and Wide Area Network (WAN) communications and network communication techniques and methods with IP compatibility for communication over the Internet.
2. Discussion of the Prior Art
Video monitoring and surveillance of locations or areas for security, safety monitoring, asset protection, process control, and other such applications by use of closed circuit television and similar systems have been in widespread use for many years. The cost of these systems has come down significantly in recent years as the camera and monitor components have steadily dropped in cost while increasing in quality. As a result, these systems have proliferated in their application and are proving extremely useful for both commercial and residential applications.
These “closed circuit television” systems typically consist of a monochrome or color television camera, a coaxial cable, and a corresponding monochrome or color video monitor, optional VCR recording devices, and power sources for the cameras and monitors. The interconnection of the camera and monitor is typically accomplished by the use of coaxial cable, which is capable of carrying the 2 to 10 megahertz bandwidths of closed circuit television systems. There are several limitations to coaxial cable supported systems. First, the cable attenuates by the signal in proportion to the distance traveled. Long distance video transmission on coaxial cable requires expensive transmission techniques. Second, both the cable, per se, and the installation is expensive. Both of these limitations limit practical use of coaxial closed circuit systems to installations requiring less than a few thousand feet of cable. Third, when the cable cannot be concealed is not only unsightly, but is also subject to tampering and vandalism.
Other hardwired systems have been used, such as fiber optic cable and the like, but have not been widely accepted primarily due to the higher costs associated with such systems over coaxial cable. Coaxial cable, with all of its limitations, remains the system of choice to the present day. Also available are techniques using less expensive and common twisted pair cable such as that commonly used for distribution of audio signals such as in telephone or office intercom applications. This cable is often referred to as UTP (twisted pair) or STP (shielded twisted pair) cable. Both analog and digital configurations are available. Both analog and digital techniques have been implemented. This general style of twisted pair cable is also widely used in Local Area Networks, or LAN's, such as the 10Base-T Ethernet system, 100 Base-T, 1000 Base-T and later systems. Newer types of twisted pair cable have been developed that have lower capacitance and more consistent impedance than the early telephone wire. These newer types of cable, such as “Category 5” wire, are better suited for higher bandwidth signal transmission and are acceptable for closed circuit video applications with suitable interfaces with special interfaces. By way of example, typical audio signals are approximately 3 kilohertz in bandwidth, whereas typical video signals are 3 megahertz in bandwidth or more. Even with the increased bandwidth capability of this twisted pair cable, the video signals at base band (uncompressed) can typically be distributed directly over twisted pair cable only a few hundred feet. In order to distribute video over greater distances, video modems (modulator/demodulators) are inserted between the camera and the twisted pair wiring and again between the twisted pair wiring and the monitor. Twisted pair cable is lower in cost than coaxial cable and is easier to install.
Wireless systems utilizing RF energy are also available. Such systems usually consist of a low power UHF transmitter and antenna system compatible with standard television monitors or receivers tuned to unused UHF channels. The FCC allows use of this type of system without a license for very low power levels in the range of tens of milliwatts. This type of system provides an economical link but does not provide transmission over significant distances due to the power constraints placed on the system. The advantage of this system over hardwired systems is primarily the ease of installation. However, the cost is usually much higher per unit, the number of channels is limited and system performance can be greatly affected by building geometry or nearby electrical interference. Further, the video is not as secure as hardwired systems. The video may be picked up by anyone having access to the channel while in range of the transmitter and is thus, easily detected and/or jammed.
Because of the inherent limitations in the various closed circuit television systems now available, other media have been employed to perform security monitoring over wider areas. This is done with the use of CODECs (compressors/decompressors) used to reduce the bandwidth. Examples include sending compressed video over standard voice bandwidth telephone circuits, more sophisticated digital telephonic circuits such as frame relay or ISDN circuits and the like. While commonly available and relatively low in cost, each of these systems is of narrow bandwidth and incapable of carrying “raw” video data such as that produced by a full motion video camera, using rudimentary compression schemes to reduce the amount of data transmitted. As previously discussed, full motion video is typically 2 to 10 megahertz in bandwidth while typical low cost voice data circuits are 3 kilohertz in bandwidth.
There are known techniques for facilitating “full motion” video over common telecommunication circuits. The video teleconferencing (VTC) standards currently in use are: Narrow Band VTC (H.320); Low Bitrate (H.324); ISO-Ethernet (H.322); Ethernet VTC (H.323); ATM VTC (H.321); High Resolution ATM VTC (H.310). Each of these standards has certain advantages and disadvantages depending upon the volume of data, required resolution and costs targets for the system. These are commonly used for video teleconferencing and are being performed at typical rates of 128K, 256K, 384K or 1.544M bit for industrial/commercial use. Internet teleconferencing traditionally is at much lower rates and at a correspondingly lower quality. Internet VTC may be accomplished at 33.6 KBPS over dial-up modems, for example. Video teleconferencing is based on video compression, such as the techniques set forth by CCITT/ISO standards, Internet standards, and Proprietary standards or by MPEG standards. Other, sometimes proprietary, schemes using motion wavelet or motion JPEG compression techniques and the like are also in existence. There are a number of video teleconferencing and video telephone products available for transmitting “full motion” (near real-time) video over these circuits such as, by way of example, systems available from AT&T and Panasonic. While such devices are useful for their intended purpose, they typically are limited in the amount of data, which may be accumulated and/or transmitted because they do not rely on or have limited compression. There are also devices that transmit “live” or in near real-time over the Internet, such as QuickCam2 from Connectix, CU-See-Me and Intel products utilizing the parallel printer port, USB port, ISA, PCI card, or PCMCIA card on a laptop computer. Many of these are personal communications systems and have neither the resolution or refresh rate required or the security required to provide for good surveillance systems. NetMeeting from Microsoft and Proshare software packages from Intel also provide low quality personal image distribution over the Internet.
All of the current low cost Network products have the ability to transmit motion or “live” video. However, such products are limited or difficult, if not impossible, to use for security applications because the resolution and refresh rate (frame rate) of the compressed motion video is necessarily low because of limited resolution of the original sample and the applications of significant levels of video compression to allow use of the low bandwidth circuits. The low resolution of these images will not allow positive identification of persons at any suitable distance from the camera for example. The low resolution would not allow the reading of an automobile tag in another example.
In many security applications it is desirable to monitor an area or a situation with high resolution from a monitor located many miles from the area to be surveyed. As stated, none of the prior art systems readily available accommodates this. Wide band common carriers such as are used in the broadcast of high quality television signals could be used, but the cost of these long distance microwave, fiber or satellite circuits is prohibitive.